Laser beam processing machine

Abstract

A laser beam processing machine comprising a chuck table for holding a workpiece, a laser beam application device for applying a laser beam to the workpiece held on the chuck table, a processing-feed device for moving the chuck table and the laser beam application device relative to each other in a processing-feed direction (X-axis direction), and an indexing-feed device for moving the chuck table and the laser beam application device relative to each other in an indexing-feed direction (Y-axis direction) perpendicular to the processing-feed direction (X-axis direction), wherein the laser beam application device includes a laser oscillation device for oscillating a laser beam, a first acousto-optic deflection device for deflecting the optical axis of a laser beam oscillated by the laser beam oscillation device in the processing-feed direction (X-axis direction), and a second acousto-optic deflection device for deflecting the optical axis of a laser beam oscillated by the laser beam oscillation device in the indexing-feed direction (Y-axis direction).

1. A laser beam processing machine comprising:
 a chuck table for holding a silicon wafer, 
 a laser beam application means for applying a plurality of pulse laser beams to the silicon wafer held on the chuck table to form a through hole therein, 
 a processing-feed means for moving the chuck table and the laser beam application means relative to each other in a processing-feed direction (X-axis direction), and 
 an indexing-feed means for moving the chuck table and the laser beam application means relative to each other in an indexing-feed direction (Y-axis direction) perpendicular to the processing-feed direction (X-axis direction), 
 wherein the laser beam application means comprises a laser oscillation means for oscillating a laser beam, a first acousto-optic deflection means for deflecting the optical axis of a laser beam oscillated by the laser beam oscillation means in the processing-feed direction (X-axis direction), and a second acousto-optic deflection means for deflecting the optical axis of a laser beam oscillated by the laser beam oscillation means in the indexing-feed direction (Y-axis direction), 
 wherein the first acousto-optic deflection means or the second acousto-optic deflection means deflects the plurality of pulse laser beams such that the beams are applied to form one through hole in a portion of the silicon wafer in which a through hole is to be formed while the wafer is moving relative to the laser beam application means, 
 wherein the first acousto-optic deflection means comprises a first acousto-optic device for deflecting the optical axis of a laser beam oscillated by the laser beam oscillation means in the processing-feed direction (X-axis direction), a first RF oscillator for applying RF to the first acousto-optic device and a first deflection angle adjusting means for adjusting the frequency of RF output from the first RF oscillator; and the second acousto-optic deflection means comprises a second acousto-optic device for deflecting the optical axis of a laser beam oscillated by the laser beam oscillation means in the indexing-feed direction (Y-axis direction), a second RF oscillator for applying RF to the second acousto-optic device, and a second deflection angle adjusting means for adjusting the frequency of RF output from the second RF oscillator, 
 wherein the first acousto-optic deflection means comprises a first output adjusting means for adjusting the amplitude of RF output from the first RF oscillator; and the second acousto-optic deflection means comprises a second output adjusting means for adjusting the amplitude of RF output from the second RF oscillator, and 
 wherein the laser beam processing means further comprises a processing-feed amount detection means for detecting the processing-feed amount of the chuck table relative to the laser beam application means, an indexing-feed amount detection means for detecting the indexing-feed amount of the chuck table relative to the laser beam application means, a memory means for storing the X and Y coordinate values of an area to be processed of the silicon wafer, and a control means for controlling the first acousto-optic deflection means and the second acousto-optic deflection means based on the X and Y coordinate values stored in the memory means and detection signals from the processing-feed amount detection means and the indexing-feed amount detection means.